The present invention relates to devices for shaping light beams, and more particularly to anamorphic prisms for shaping light beams.
Light beam shaping devices are commonly utilized in connection with laser diodes. The geometry of the emitting area of a laser diode is typically nonsymmetrical such that the light emitted from the diode is cross-sectionally elliptical. Usually the major axis of the elliptical cross-section light is about twice that of the minor axis, and thus, the orthogonal dimensions of the light typically have a ratio of about two to one. It is advantageous in a variety of applications to reshape the elliptical cross-section light to a circular cross-section through use of a shaping device. Ordinarily, the shaping device is used in combination with a collimator so that the output light is not only reshaped, but also collimated.
Prior art beam shaping devices may be broadly classified into two categories, namely, lenses and prisms. Lens systems are advantageous in that they not only maintain the direction of the input beam, but also maintain colinearity between the input and the output beam, such that they lie along a common axis. However, lens systems typically involve the forming of complex surfaces which require precise manufacturing tolerances, and thus they are quite expensive to manufacture. Further, the optical elements associated with lens systems must be maintained in relatively precise alignment for proper operation. Prism systems, on the other hand, are less expensive to manufacture, but typically do not provide colinearity of the input and output beams. Further, in prior art systems, it is necessary to utilize at least two separate prisms to maintain the direction of the input and output beams. These prism systems, therefore, require multiple optical elements and thus also suffer from alignment problems, although the tolerances are typically less than for the lens systems.
Accordingly, there is a need in the art for a prismatic shaping device which reduces alignment problems, and maintains the direction of the input and output beams, as well as providing colinearity of such input and output beams.